1. Field of the Invention
The present invention relates to an image sensing arrangement having a solid-state image sensing device for converting an image of an object to be photographed into an electrical signal and, more particularly, to an image sensing arrangement which has the single photography mode for photographing an object image only once and the continuous photography mode for continuously photographing the object image.
2. Description of the Prior Art
With recent advances in IC techniques, solid-state image sensing devices such as CCDs are used in video cameras or the like.
An electronic recording camera is known which uses a solid-state image sensing device of the type as described above on the imaging surface of an imaging lens. The object image is formed on the image sensing device which produces an image signal which is then recorded on a magnetic recording medium, thus taking a picture of the object.
A solid-state image sensing device of the type as described above allows control of the level of the image signal of the image formed thereon, that is, allows control of exposure. Therefore, the device is advantageous in that a picture may be taken without requiring a mechanical shutter as in the case of a conventional camera. However, with a solid-state image sensing device of the type described above, blooming of the stored image data may be caused under the condition of high luminance. Furthermore, in an electronic recording camera of the type described above, a magnetic recording means comprising a solid-state image sensing device or the like requires several seconds before it may be driven in the steady state; power must be supplied to the magnetic recording means before a picture is taken.
In this camera, the object image is formed on the solid-state image sensing device and the object image is stored as the image signal. In this manner, the object image is converted into the image signal by the solid-state image sensing device, and the image signal stored on the solid-state image sensing device is thereafter transferred to the magnetic recording medium. Accordingly, the storing operation of the image signal corresponds to the exposure time of a camera using a general photosensitive film; power must be supplied to the circuit until exposure is completed or the storing operation of the image signal is completed as in a general camera. In an electronic recording camera of the type described above, unlike a conventional camera, the photography cycle is not completed even if the exposure or image signal storage is completed. That is, after the image signal is stored, the image signal stored in the solid-state image sensing device must be transferred to the magnetic recording medium. Since the image signal is transferred serially, it takes a predetermined period of time before image signal transfer is completed.
A solid-state image sensing device consists of a plurality of picture elements which respectively store the image signals. Therefore, the image signals stored in the respective picture elements are serially read out to be recorded on the recording medium. Transfer of image signals thus requires a predetermined period of time. In an electronic recording camera, power must be supplied until the transfer operation is completed even after exposure is completed.
When a camera is of the diaphragm priority type, the storing time of the solid-state image sensing device must be controlled by an output from a photometer. A complex circuit is required to control the storing time, and the photographing interval changes for each picture in accordance with an output from the photometer. In the continuous photography mode, it is generally desired that the photographing interval be kept constant. The camera of the type described above fails to satisfy this requirement if it is of the diaphragm priority type.
In the continuous photography mode, the exposure time is preferably kept constant. If the exposure time is kept constant and if a picture is taken with an aperture diaphragm set for diaphragm priority in the single photography mode, optimal exposure may not be obtained; the aperture diaphragm must be manually adjusted in accordance with exposure time and luminance. If the user performs continuous photography with an aperture diaphragm set in the diaphragm priority mode, optimal exposure is not obtained.